Invention 9 BWV 780 sounding in the key of F minor is a challenging invention to play particularly from the note reading and voice leading point of view. There are many accidentals to read and it is easy to make music reading errors. This is an excellent movement to encourage good intonation in duet playing. There are some octave transpositions in the trombone part. A legato playing approach is required in the playing in what is a slow tempo and melancholy movement. Playing the F minor scale in both its melodic and harmonic form slowly would be excellent preparation for playing this movement. In the sheet music score the ornaments are indicated but do not sound. Both the bass and tenor clefs have been used in the notation of the score. The realisation plays back at 54 quarter note or crotchet beats per minute. Accompaniments are in place allowing trumpet and trombone players to participate in ensemble activities as part of practice routines. The trumpet in Bb sounds on one side of the stereo channel and the trombone on the other. The accompaniment tracks play back at 50, 52, 54, 56, 58, 60 & 62 quarter note (crotchet) beats per minute. There is a two bar count in /click track at the beginning of the accompaniment tracks. In the keyboard video score, which trombonists may wish to refer to on the PlentyMusic YouTube channel ornaments have been written out as they sound in the realisation to represent exactly what is being played. The Bach Inventions are generally considered to be intermediate level movements when played on a keyboard instrument. The principle behind J. S. Bach’s two part inventions is to take a musical idea or motive and then process it following the rules of good contrapuntal writing using the compositional processes of the baroque and at the same time referencing the closely related keys in the key system. Inversion, repetition, sequence, transposition, rhythmic augmentation & diminution & other processes are evident in Bach’s Inventions as most other music of the baroque period. J. S. Bach composed 15 Inventions in a collection dating from 1723 intended to introduce keyboard players to composition techniques of the baroque. They are excellent ensemble movements.
